Apparatus and method for verifying print quality of an encoded indicium

ABSTRACT

The invention is an apparatus configured to provide self-alignment in use when measuring the print quality of an encoded indicium. The apparatus is configured to exclude ambient light, and to align an encoded indicium located at a first aperture defined in a first surface of the apparatus with an imager positioned at a second aperture defined in a second surface of the apparatus. A source of illumination is provided to illuminate the encoded indicium during an interval when the encoded indicium is undergoing a verification process. An illumination control is provided to control the source of illumination. The apparatus can be controlled using a computer and a computer program recorded on a machine-readable medium.

COPYRIGHT NOTIFICATION

Portions of this patent application contain materials that are subjectto copyright protection. The copyright owner has no objection to thefacsimile reproduction by any person of the patent document as itappears in the patent file or records after it is publicly availablefrom the United States Patent and Trademark Office, but otherwisereserves all copyright rights whatsoever.

FIELD OF THE INVENTION

The invention relates to verifiers for encoded indicia in general andparticularly to a verifier that employs a hollow chamber to controloperating features of the verifier.

BACKGROUND OF THE INVENTION

Verifiers, as the term is used herein, are devices that are used tomeasure encoded indicia and to provide qualitative and/or quantitativeanalysis of the suitability of the encoded indicia for particularapplications, i.e., a measurement of the quality of the encodedindicium, or qualification of the encoded indicium. Verifiers used toexamine encoded indicia comprising one-dimensional (1D) andtwo-dimensional (2D) bar codes, optically recognized characters, andother optically observable symbols are well known. Optical verifiersdescribed in the patent literature for examining encoded indicia includethose that use laser scanners, those that use linear arrays of opticaldetectors such as charge-coupled devices (CCDs), and those that usetwo-dimensional arrays of optical detectors, such as CCD arrays andvidicons. In general, the verifiers that have been described in theliterature are reported to be useful in the analysis of the quality ofencoded indicia over the widest possible range of conditions, includingoperation at arbitrary and variable distances, operation under a varietyof ambient illuminating conditions, and operation using moving encodedindicia as targets for qualification.

Certain standards for qualifying various encoded indicia have beenavailable for some time, such as American National Standards Institute(ANSI) Specification “Bar Code Print Quality Guideline” X3.182-1990 andthe “UPC Symbol Specification Manual” and “Quality Specification for theUPC Printed Symbol”, published by the Uniform Code Council, Inc.,Dayton, Ohio 1993. The ANSI specifications assign a letter grade, “A”through “F”, to the encoded indicium based on the lowest letter gradeobtained on several different test parameters.

The prior art verifier systems suffer from various problems. Forexample, one prior art system requires the user to calibrate theverifier before each usage, in order to determine a working distance andorientation to a target encoded indicium. The calibration procedurerequires at least one calibration standard, and may require multiplecalibration standards. In some prior art systems, the user mustconfigure the imaging system to obtain a spot size at the target encodedindicium according to the requirements of the ANSI specification. Someprior art systems require the user to manually orient the imager (or anextension thereof) used to obtain an image of the target encodedindicium so that a plurality of switches or contact indicators aresimultaneously activated before the verifier can operate. Other priorart systems require the user to confirm visually that the imager iscorrectly aligned with the target encoded indicium.

There is a need for a verifier that is simple and convenient to operate,but that overcomes all of the shortcomings of the prior art.

SUMMARY OF THE INVENTION

A verifier system that overcomes all of the above enumerateddifficulties and limitations, but that is nevertheless simple andconvenient for a user to operate is disclosed herein. The inventivesystem provides all of the benefits of a verifier system that would befound in a high quality darkroom laboratory setting, but that eliminatesmany, if not all, of the tedious details of setting up a darkroom-typeverification apparatus as would be found in a laboratory setting.Briefly stated, the system comprises a hollow chamber configured toprovide a view of the target encoded indicium, configured to supporteach of a plurality of different types of imaging sensors at a distanceand angle calculated to provide an optimal view of the encoded indicium,and configured to support on the interior surface of the chamber one ormore sources of illumination configured to illuminate the target encodedindicium with controlled illumination intensity. The hollow chamber isconfigured to exclude ambient illumination. The system can be calibratedas necessary using a single calibration standard, but need not becalibrated before each use, or before any particular use. The user isnot required to visually align the target encoded indicium and theimaging sensor; rather, the alignment is automatically provided by theproper assembly of the system using the hollow chamber according toprinciples of the invention.

In one aspect, the invention relates to a self-aligning structure foruse in measuring the quality of an encoded indicium. The self-aligningstructure comprises a hollow chamber that comprises a first surfacedefining a first aperture, the first aperture representing a viewingarea of an imager used to obtain an image of the encoded indicium; asecond surface defining a second aperture, the second apertureconfigured to support the imager in a position to obtain the image ofthe encoded indicium; at least one source of illumination situatedwithin the hollow chamber, the at least one source of illuminationconfigured to illuminate the encoded indicium; and an illuminationcontrol operatively coupled to control the at least one source ofillumination. The hollow chamber is configured to be positioned adjacentthe encoded indicium such that, when the encoded indicium is positionedwithin the viewing area, when an imager is supported in the secondaperture, and when the at least one illumination source is properlycontrolled, the structure is self-aligned and the imager can obtain atleast one image of the encoded indicium from which image the quality ofthe encoded indicium can be measured.

In one embodiment, the hollow chamber is configured to excludeextraneous illumination when the imager is present and the hollowchamber is positioned adjacent the encoded indicium. In one embodiment,the hollow chamber is configured to support the imager in a definedposition relative to the encoded indicium. In one embodiment, thedefined position comprises a defined distance. In one embodiment, thedefined position comprises a defined angle. In one embodiment, thehollow chamber is constructed in a plurality of sections, a firstsection comprising the first surface defining the first aperturerepresenting the viewing area of the imager of the encoded indicium, anda second section comprising the second surface defining the secondaperture configured to support the imager in the position to obtain theimage of the encoded indicium. In one embodiment, the hollow chamber isconfigured to remain mechanically stable when the imager is positionedwithin the second aperture. In one embodiment, the hollow chamberfurther comprises an optical sensor configured to receive illuminationfrom the at least one source of illumination for the purpose ofconfirming an illumination characteristic provided by the at least onesource of illumination. In one embodiment, the illuminationcharacteristic provided by the at least one source of illumination is acharacteristic selected from an illumination intensity at a selectedtime and an illumination wavelength.

In another aspect the invention features an image quality verifiersystem useful for verifying the quality of an encoded indicium. Theimage quality verifier system comprises an imager for obtaining an imageof the encoded indicium, and a self-aligning structure. Theself-aligning structure comprises a hollow chamber that comprises afirst surface defining a first aperture, the first aperture representinga viewing area of the imager; a second surface defining a secondaperture, the second aperture configured to support the imager in aposition to obtain the image of the encoded indicium; at least onesource of illumination situated within the hollow chamber, the at leastone source of illumination configured to illuminate the encodedindicium; and an illumination control operatively coupled to control theat least one source of illumination. The imager obtains at least oneimage of the encoded indicium from which image the quality of theencoded indicium can be measured when the encoded indicium is positionedwithin the viewing area, the imager is supported in the second aperture,and the at least one illumination source is properly controlled.

In one embodiment, the imager comprises a sensor having a linear arrayof photosensitive elements. In one embodiment, the imager comprises asensor having a two-dimensional array of photosensitive elements. In oneembodiment, the imager is a selected one of a one-dimensional bar codereading apparatus and a two-dimensional bar code reading apparatus.

In one embodiment, the image quality verifier system further comprisesan analysis module configured to provide a measure of quality of aparameter of an encoded indicium undergoing verification relative to thesame parameter of the reference encoded indicium.

In one embodiment, the image quality verifier system further comprises amemory module configured to record data indicative of a parameter of thereference encoded indicium.

In one embodiment, the hollow chamber is configured to remainmechanically stable when the imager is positioned within the secondaperture. In one embodiment, the hollow chamber further comprises anoptical sensor configured to receive illumination from the at least onesource of illumination for the purpose of confirming an illuminationcharacteristic provided by the at least one source of illumination. Inone embodiment, the illumination characteristic provided by the at leastone source of illumination is a characteristic selected from anillumination intensity at a selected time and an illuminationwavelength.

In still a further aspect, the invention relates to a method ofmeasuring the quality of an encoded indicium. The method comprises thesteps of providing a self-aligning structure for positioning an imagerin relation to an encoded indicium, the self-aligning structureconfigured to permit the imager to view the encoded indicium andconfigured to exclude ambient light; illuminating the encoded indiciumwith at least one source of illumination contained within theself-aligning structure; operating the imager to obtain at least oneimage of the encoded indicium; and measuring the quality of the encodedindicium from the image.

In one embodiment, the step of providing a self-aligning structurecomprises positioning the self-aligning structure relative to an encodedindicium so that the encoded indicium is situated so as to be visiblewithin a first aperture defined in a first surface of the self-aligningstructure; and positioning the imager within a second aperture definedin a second surface of the self-aligning structure.

In one embodiment, the method further comprises the step of measuring areference encoded indicium to obtain a reference parameter forcalibrating the quality measurement.

In one embodiment, the method further comprises the step of monitoring acharacteristic of the illumination provided by the at least one sourceof illumination.

In one embodiment monitoring a characteristic of the illuminationprovided by the at least one source of illumination comprises monitoringa selected one of an illumination intensity at a selected time and anillumination wavelength.

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent from the following descriptionand from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention can be better understood withreference to the drawings described below, and the claims. The drawingsare not necessarily to scale, emphasis instead generally being placedupon illustrating the principles of the invention. In the drawings, likenumerals are used to indicate like parts throughout the various views.

FIG. 1 is a perspective drawing showing features of one embodiment of aself-aligning structure for use in measuring the quality of an encodedindicium, according to principles of the invention;

FIG. 2 is a perspective exploded view drawing showing features ofanother embodiment of a self-aligning structure for use in measuring thequality of an encoded indicium, according to principles of theinvention;

FIG. 3 is a drawing showing features of a system for measuring thequality of an encoded indicium that comprises a self-aligning structure,according to principles of the invention;

FIG. 4 is a flow diagram showing at a high level an illustrativeembodiment of a process of measuring the quality of an encoded indicium,according to principles of the invention;

FIG. 5A shows an embodiment of the self-aligning image quality verifiersystem that employs a user interface screen on a video display;

FIG. 5B shows another view of an embodiment of the self-aligning imagequality verifier system that employs a user interface screen on a videodisplay;

FIG. 6 is a screen shot that depicts an embodiment of the toolbar ofFIG. 5A in greater detail;

FIG. 7 shows a screen shot of an embodiment of a configuration menuaccording to principles of the invention;

FIG. 8 is a screen shot of an embodiment of a menu that permits a userto select the number of scans to be taken per symbol, according toprinciples of the invention;

FIG. 9 is a screen shot of a portion of the user interface screen ofFIG. 5A that shows overall symbol or encoded indicium grade results,according to principles of the invention;

FIG. 10 is a screen shot of an embodiment of a region of the userinterface screen that presents general data to a user;

FIG. 11 is a screen shot of an embodiment of region of FIG. 5A thatdisplays parameters relating to reflectance properties of the symbolbeing scanned or under verification;

FIG. 12 is a screen shot depicting a region of FIG. 5A that displays theISO/IEC scan grade attained by scanning an encoded indicium;

FIG. 13 is a screen shot of a region of FIG. 5A that displays the formatresults attained by scanning an encoded indicium;

FIG. 14 is a screen shot showing a region of FIG. 5A that displaysvarious dimensional parameters associated with an encoded indiciumundergoing verification;

FIG. 15 is a screen shot of a region of FIG. 5A that shows certaininformative and graded results as a list of text messages; and

FIG. 16 is a screen shot of a region of FIG. 5B comprising a status bar.

DETAILED DESCRIPTION OF THE INVENTION

In order to overcome such difficulties of set-up, calibration andoperation as have been described in the section captioned “Background”hereinabove, the systems and methods proposed herein as embodiments ofthe invention rely on a self-aligning verifier structure comprising ahollow chamber. As will be explained presently, the self-aligningstructure provides for the proper alignment and spacing of a targetencoded indicium to be examined for quality (or “verified”) with regardto an image sensor selected from a variety of possible image sensortypes that are available for use. The system further excludes ambientillumination, and provides controlled illumination during theexamination of the target encoded indicium to be verified. Since theimage sensor and the target encoded indicium do not move during theverification process, alignment is a straightforward process, and isbased on distances, angles of view, and illumination levels that havebeen pre-calculated for a target encoded indicium of a known kind andfor an image sensor of a known kind. Alignment and exposure levels areassured to the extent that the system is properly assembled and theillumination source is functional and properly controlled. An opticalsensor that serves to check the illumination level, the illuminationwavelength, and the time in which the illumination source is active isoptionally provided.

Turning to FIG. 1, there is a perspective drawing showing features ofone embodiment of a self-aligning structure 100 for use in measuring thequality of an encoded indicium. The self-aligning structure 100comprises a hollow chamber 101. In one embodiment, the hollow chamber101 has a trapezoidal cross section in elevation, as shown in FIG. 1.However, other shapes for the elevation of the hollow chamber 101 arealso suitable for use as a self-aligning structure, such as arectangular shape, a cubic shape, a pyramidal shape comprising at leastthree sides, or a curved shape, such as a hemispherical shape. Thehollow chamber 101 comprises a first surface 102 defining a firstaperture 104. The first aperture 104, shown in phantom, represents aviewing area of an imager (not shown in FIG. 1, but see FIG. 3) that isused to obtain an image of an encoded indicium 120. In FIG. 1, encodedindicium 120 is shown for simplicity as a linear or one-dimensional barcode. However, those of ordinary skill will recognize that the encodedindicium can be any encoded representation of information, such astwo-dimensional bar codes, or stacked bar codes. The hollow chamber 101can be positioned adjacent the encoded indicium 120 such that theencoded indicium 120 is positioned within the viewing area defined bythe first aperture 104. As necessary, an opaque gasket is provided onthe undersurface of surface 102 in a closed locus outside the dimensionsof first aperture 104 to optically seal the encoded indicium 120 fromextraneous light that might otherwise enter laterally (e.g., in adirection substantially parallel to the plane of the encoded indicium120).

As shown in FIG. 1, the hollow chamber 101 comprises a second surface106 defining a second aperture 108. The second aperture 108 isconfigured to support the imager in a position to obtain the image ofthe encoded indicium 120. The imager can be any conventional imagerknown in the art, and in particular can be an imager such as isdescribed in U.S. patent application Ser. No. 10/092,789, which isassigned to the assignee of this application, the disclosure of which isincorporated by reference herein in its entirety.

In the embodiment shown in FIG. 1, the hollow chamber 101 also comprisesat least one source of illumination 110 situated within the hollowchamber 101. The at least one source of illumination 110 is configuredto illuminate the encoded indicium 120. In other embodiments, the imagercan comprise a source of illumination for illuminating a target encodedindicium 120. An illumination control (not shown in FIG. 1, but see FIG.3) is operatively coupled to control the at least one source ofillumination, or alternatively, to control a source of illuminationprovided by an imager. The illumination control can in variousembodiments be any one of a control that operates in response toinstructions from an operator of the apparatus, that operates inresponse to instructions from the imager, or that operates in responseto instructions from a computer used in conjunction with theself-aligning structure 100 and the imager. The hollow chamber 101 isconfigured to be positioned adjacent the encoded indicium 120 such that,when the encoded indicium 120 is positioned within the viewing area 104,when an imager is supported in the second aperture 108, and when the atleast one illumination source 110 is properly controlled, the imager canobtain at least one image of the encoded indicium 120 from which imagethe quality of the encoded indicium 120 can be measured.

The at least one image of the encoded indicium 120 is preferablyobserved under controlled conditions of illumination. In order tocontrol the illumination, the hollow chamber 101 is configured toexclude extraneous illumination when the imager is present and thehollow chamber is positioned adjacent the encoded indicium 120. The atleast one illumination source 110 (or the alternative source ofillumination provided by the imager) is controlled to provide apredetermined illumination level during the time that the imager isoperating so that the conditions of measurement of the encoded indiciumare well defined, and extraneous illumination, that would beuncontrolled, is excluded.

The hollow chamber 101 is configured to support the imager in a definedposition relative to the encoded indicium 120. The defined positioncomprises at least one of a defined distance and a defined angle. Theimager is thereby provided a defined view of the encoded indicium 120.As needed, an adapter piece can be interposed between the secondaperture 108 and the imager, for purposes of defining one or more of thedistance and angle, and/or for purposes of assuring a light-tightconnection (e.g., an opaque gasket) between the hollow chamber 101 andthe imager at the second aperture 108.

FIG. 2 is a perspective exploded view drawing 200 showing features ofanother embodiment of a self-aligning structure for use in measuring thequality of an encoded indicium, in which the hollow chamber 101 isconstructed in a plurality of sections. A first section 210 comprisesthe first surface 102 defining the first aperture 104 representing theviewing area of the imager of the encoded indicium 120. A second section220 comprises the second surface 106 defining the second aperture 108configured to support the imager in the position to obtain the image ofthe encoded indicium 120. A self-aligning structure constructed using aplurality of sections allows the measurement of a variety of encodedindicia 120 with a variety of imagers. The first section 210 and thesecond section 220 are designed to be oriented so that apertures 104 and108 are suitably positioned and oriented relative to one another. Asshown in the embodiment illustrated, the orientation of the two sections210, 220 can be maintained to within 180 degrees by having unequaldimensions of length L and width W. In another embodiment, there can beunequal dimensions on at least three sides. In a further embodiment,there can be unequal angles at the junctions of pairs of adjacent sides,for example if the cross section of the self-aligning structure at themating surface is a trapezoid, so that the two sections can have onlyone relative orientation upon mating. Alternatively, or additionally,there can be mating keys and keyways, or mating flange surfaces, sodisposed that sections 210, 220 will be able to mate together only inthe appropriate relative orientation. In the embodiment shown, the firstsection 210 has an effective height H₁ and the second section 220 has aneffective height H₂.

Different imagers are designed to operate at different working distancesfrom the encoded indicia that they are required to read. Differentencoded indicia can have different shapes and sizes. For example, topermit the use of different imagers having different working distances,a first section 210 may be used having a defined aperture 104 thatallows an encoded indicium of type A to be viewed. A plurality of secondsections 220, 220′, each configured to support a particular imager, maybe used with the same first section 210 to measure the quality ofencoded indicia of type A. Each respective second section 220, 220′ hasa second aperture 108, 108′ configured to mate with a particular imager,and has dimensions designed to position the respective imager at thepredetermined distance and/or predetermined angle with respect to theencoded indicium 120 to be imaged. By way of example, the first section210 can be designed with a mating surface 212 at a predetermined height(H₁), such as one inch, above the first surface 104. Each second section220, 220′ can be designed to have the required height (H₂) to define thedistance from the encoded indicium 120 to the imager to be H₁+H₂, aswell as having suitable angular orientation, and suitable illuminationprovided by the at least one illumination source 110. A different firstsection 210′ can be provided having a defined aperture 104′ that allowsan encoded indicium of type B to be viewed. Accordingly, one canconfigure a suitable self-aligning optical verifier for verifying anencoded indicium selected from one of Type A and Type B with either of afirst imager or a second imager merely by assembling the correct firstand second sections as necessary. As needed, an optically opaque gasketis provided at the mating surfaces of the first and second sections.Whether constructed in one section or in a plurality of sections, thehollow chamber 101 is configured to remain mechanically stable when theimager is positioned within the second aperture 108.

FIG. 3 is a drawing showing features of a self-aligning image qualityverifier system 300 for measuring the quality of an encoded indiciumthat comprises a self-aligning structure 100 such as that described inconjunction with FIGS. 1 and 2. Having described the self-aligningstructure 100 in detail, it will not be described further. The system300 comprises an imager 310 for obtaining an image of the encodedindicium 120, and a hollow chamber 101. The imager 310 obtains at leastone image of the encoded indicium 120 from which image the quality ofthe encoded indicium 120 can be measured when the encoded indicium 120is positioned within the viewing area 104, the imager 310 is supportedin the second aperture 108, and the at least one illumination source 110is properly controlled.

The self-aligning image quality verifier system 300 can comprise any ofa variety of imagers 310. In one embodiment, the imager 310 comprises asensor having a linear array of photosensitive elements. In anotherembodiment, the imager 310 comprises a sensor having a two-dimensionalarray of photosensitive elements. As already mentioned, in variousembodiments, the imager 310 is a selected one of a one-dimensional barcode reading apparatus and a two-dimensional bar code reading apparatus.In still other embodiments, the imager 310 can be an imager 310 providedas a component of a portable device such as a portable data terminal(PDT) or a personal digital assistant (PDA). The imager 310 can beinternal to the portable device, or can be attached to the portabledevice, for example with an electrical cable comprising one or moreconductors. In one embodiment, the portable device can store image dataobtained by the imager 310, and at a later time, can transfer the storedimage data to another data processing system, such as a centralized dataprocessing system. The data can be transferred by wire or by wirelesscommunication technology. The data can be transferred in a formcorresponding to the form in which it is obtained by the imager 310, orin a form corresponding to processed data that is different from theform in which it is obtained from the imager 310.

The self-aligning image quality verifier system of FIG. 3 can furthercomprise an analysis module 320. The analysis module 320 can be integralwith the imager 310, as shown, or in alternative embodiments, can beoperatively connected to imager 310 by way of a wired connection such asa USB or RS-232 connection, a bus connection, or a wireless connectionsuch as a radio or infrared communication connection. The analysismodule 320 is configured to provide a measure of quality of a parameterof an encoded indicium 120 undergoing verification relative to the sameparameter of a reference encoded indicium 130. In one embodiment, theanalysis module 320 is a program module operating on a microprocessor.The image quality verifier system 300 can also comprise a memory module330 configured to record data indicative of a parameter of the referenceencoded indicium 130 and/or a parameter of the encoded indicium 120undergoing verification. The memory module 330 in one embodiment isprovided as part of the analysis module 320, for example as a memorychip on a computer motherboard, or as memory on a microprocessor chipactive as the analysis module 320. In other embodiments, the memorymodule 330 is a separate memory segment within a conventional memorydevice such as a semiconductor memory device (e.g., RAM, SDRAM), amagnetic memory device (e.g., floppy or hard disk), or an optical memorydevice (e.g., CD-ROM, CD-R or CD-RW disc) that is in communication withthe analysis module 320. Optionally, an illumination detector 340 issituated in visual communication with the at least one illuminationsource 110. The illumination detector 340 monitors the illuminationsource 110, to monitor a characteristic of the illumination provided bythe at least one source of illumination, such as monitoring a selectedone of an illumination intensity at a selected time and an illuminationwavelength. The period of operation of the illumination source 110 canconveniently be determined by repetitively interrogating theillumination detector 340 over time. The illumination detector 340 is incommunication with an illumination control module 350 that controls theat least one illumination source 110. Thus, if the illuminationcharacteristic monitored by illumination detector 340 falls outside adesired range, a signal, which in some embodiments can be an errorsignal, is communicated to the illumination control module 350, and theillumination control module 350 takes corrective action usingconventional feedback principles of operation.

In one embodiment, the self-aligning image quality verifier systemcomprises a computer program (i.e., software) recorded on amachine-readable medium, which when operating on a programmable computercontrols a process comprising a plurality of steps. The machine-readablemedium can be any conventional machine-readable medium, for examplemedia ranging from punched cards or punched paper tape to magneticstorage media such as floppy or hard disks, magnetic tape or magneticwire, to semiconductor media such as RAM, ROM, and EPROM, and opticalmedia such as CD-ROM, CD-R and CD-RW discs. The process controlled bythe computer program is described at a high level in the flow chartshown in FIG. 4. In one embodiment, the computer upon which the computerprogram operates is present within the imager 310. In other embodiments,the computer upon which the computer program operates is operativelycoupled to the imager 310, and may be a general purpose computer of anyconventional type, such as an Intel Pentium-based personal computer, ora computer such as those available from Apple Computer, Inc., includinga laptop computer, a desktop computer, or a handheld computer.

FIG. 4 is a flow diagram 400 showing at a high level an illustrativeembodiment of a process of measuring the quality of an encoded indicium,according to principles of the invention. The flow diagram begins atoval 410, labeled “START,” corresponding to setting up the hardware andinitializing the software as necessary. The user then can optionallycalibrate the self-aligning image quality verifier system, as indicatedat box 420, labeled “OPTIONALLY PERFORM CALIBRATION.” If the calibrationis elected, the user places a calibration standard encoded indicium of atype corresponding to the intended target encoded indicium in theviewing area of the self-aligning image quality verifier system, andcommands the system to take measurements. In general, if a calibrationstandard encoded indicium is used that is of acceptable quality, all ofthe images and associated parameters will return results that indicateacceptable quality for the calibration standard encoded indicium. Thecomputer program of the system uses the measured image data obtainedfrom the calibration standard encoded indicium to verify that the systemis behaving appropriately, rather than to obtain calibration constantswith which to later scale information obtained from an encoded indiciumundergoing verification. The computer program of the system operates theapparatus in such a manner that the dynamic range observed by the imagerwhen imaging the calibration standard encoded indicium is withinsuitable tolerances for a measurement. The measurement process forexamining the quality of an encoded indicium includes the control of notonly the distance and orientation between the encoded indicium and theimager, but also the illumination level within the apparatus as aconsequence of the control of the at least one illumination source.Therefore, the apparatus and process can define a dynamic range orcontrast level range for the calibration standard encoded indicium bycontrolling the illumination level. Operation to measure the quality ofan encoded indicium undergoing testing can then be performed using thesame illumination level and operating conditions. Accordingly, if theuser has reason to believe that the system is behaving appropriately,the calibration step 420 can be safely omitted. Details of theparameters and results that can be expected will be discussedhereinbelow. The image information obtained from the calibrationstandard encoded indicium, when collected, is compared with absolutevalues that correspond to the substantially theoretical values thatwould be obtained for the measurement of a “perfect” calibrationstandard encoded indicium with a “perfect” verifier apparatus. Inparticular, the self-aligning image quality verifier system can beadjusted, for example by adjusting the illumination level, and adjustingoperating parameters of the image sensor, to bring the observed imageinformation from the calibration standard encoded indicium into closeagreement with the theoretical values if the calibration standardencoded indicium has not been damaged or degraded. By comparison, othersystems using ambient light need to calibrate their operating parametersto accommodate the then-incident level of illumination, which is subjectto variation with time as a result of uncontrolled changes that mayhappen to occur, which can cause changes in both the absoluteillumination level and the spectral content of the ambient illumination.

Upon completion of the elected calibration, or if the calibration isomitted, the user next places the intended target encoded indicium inthe viewing area of the self-aligning image quality verifier system, andcommands the system to take measurements, as indicated at box 430,labeled “IMAGE ENCODED INDICIUM.” In response to a command to make ameasurement, the self-aligning image quality verifier system activatesthe image sensor 310 to obtain at least one image of the encodedindicium 104 undergoing verification. As indicated at box 440, labeled“ANALYZE,” the self-aligning image quality verifier system operates uponreceipt of the command to measure according to the instructions providedin the computer program operating on the computer, so as to comprise ananalysis module 320, and proceeds to analyze the at least one image ofthe encoded indicium undergoing verification to extract therefromparameters that provide information regarding the quality of an encodedindicium of the type of the encoded indicium undergoing verification. Aspart of the analysis process, the analysis module 320 can store andretrieve from memory module 330 information relating both to the rawimage data and to the results of analysis of the raw image data. Theanalysis module 320 compares data from the measurement of the encodedindicium undergoing verification with data corresponding to thetheoretical values that would be obtained for the measurement of a“perfect” calibration standard encoded indicium with a “perfect”verifier apparatus. Since the apparatus is expected to be operatingsatisfactorily, and can be checked by performing an optional calibrationstep 420, it is expected that parameters observed for the encodedindicium undergoing verification that deviate from suitable values areattributable to flaws in the quality of the encoded indicium undergoingverification, and are so reported. The reported results are presented tothe user, and can be alternatively and/or additionally recorded onmachine-readable media for later use or for archival purposes, asindicated at box 450, labeled “REPORT RESULTS.” The report can be in anyconvenient form, ranging from a simple aural or visual signalcorresponding to acceptable or unacceptable results, to a complete,detailed description as explained at greater length hereinbelow.

The system then prompts the user to respond to the question as towhether any additional encoded indicia are available for verificationanalysis, as indicated by the diamond 460, labeled “ANOTHER INDICIUM?”If there are no further encoded indicia that are to be subjected toverification analysis, the process can be terminated, as indicated atoval 470, labeled “END.” However, if there are additional indicia to besubjected to verification analysis, the process proceeds to box 465,labeled “OPTIONALLY REPEAT.” The user then has the option as to whethera calibration step should be performed, as indicated by the arrowleading from box 465 to box 420, or whether the calibration step shouldbe omitted, as indicated by the arrow leading from box 465 to box 430.Operation then continues according to the user's selection, as describedhereinabove.

The operation of the self-aligning image quality verifier system willnow be described using one embodiment that employs a personal computer.FIG. 5 shows an embodiment of the self-aligning image quality verifiersystem that employs a user interface screen 500 on a video display. Theuser interface screen 500 provides information to the user about theoperation of the system as well as data about the quality of an encodedindicium undergoing verification. The user interface screen 500comprises one or more display formats selected from a graphical userinterface (“GUI”), text information, numerical information, visualindicators such as lights, and combinations thereof. In addition,audible signals may optionally be provided. The software used to operatethe self-aligning image quality verifier system can be prepared usingany convenient programming language, such as C, C++, Visual Basic,assembler, and/or other well-known programming languages, as well ascombinations of computer modules and routines created using differentcomputer programming languages. The operating system used by thecomputer that operates according to the commands encoded in the softwarecan be any operating system, including such systems as Windows™ in anyof its variants, Unix in any of its variants, Linux, any of theoperating systems provided by Apple Computer, Inc., and other well-knownoperating systems.

As may be seen in FIG. 5A, in one embodiment the software is an activeapplication operating on a personal computer in a Microsoft Windows™environment, as indicated by the icon 500′ at the bottom of the screen,which is displayed in the commonly observed “brighter” or “selected”status indicative of the current foreground application. The reader canobserve that the environment also includes an instantiation of a wordprocessing program, represented by the pane 501 in the background andthe icon 502 on the bottom navigation bar, and various directories,represented by the file folder icons 503, 503′: The user interfacescreen 500 comprises a variety of regions including: a toolbar 510, a“pull-down” menu bar 515, and a plurality of regions 520, 530, 540, 550,560, 570 and 580, that will be discussed in more detail hereinbelow inturn. As may be observed in region 520, the embodiment shown in FIG. 5is an application called “QUICK CHECK® PC600.” QUICK CHECK® is atrademark of HHP, Inc. Various features of the application are protectedby copyright as indicated by the notation “Copyright© 2003 HHP AllRights Reserved” that appears in the lower left hand corner of region540.

FIG. 6 is a screen shot that depicts an embodiment of the toolbar 510 ingreater detail. The toolbar 510 comprises GUI buttons 602 through 630.Button 602 when activated opens an existing data file, for example forreview or for analysis. The data file is recorded on a machine-readablememory. Button 604 when activated saves an active file to amachine-readable memory. Button 606 when activated causes the printingof a report. Button 608 when activated opens a configuration menu, thatallows a user to select a port for operation of the verifier apparatus,and that allows the user to configure report formats and contents, suchas the menu depicted in FIG. 7, described in more detail below. Button610 when activated opens a user interface that permits the user toselect the number of scans to be used in evaluating an encoded indiciumor a symbol, as is depicted in FIG. 8, described in more detail below.

Button 612 when activated causes the display of the previous scan in agroup of scans of a symbol. Button 614 when activated displays the nextscan in a group of scans. Button 616 when activated opens a scanreflectance profile display. Button 618 when activated opens an elementwidth analysis display, elements being the components of the encodedindicium or symbol, for example for a black and white one dimensionalbar code, the light and dark, or more reflective and less reflectivestripes comprising the bar code. Button 620 when activated causes theuser to be prompted for data to be used in calculating the X dimensionof a scan. The X dimension of a bar code is the dimension of itsnarrowest element. Button 622 when activated presents a display for theuser to make and edit notes for the group of scans. Button 624 whenactivated causes the real-time display of reflectance data from theverifier apparatus. Button 626 when activated presents to the user anindex of topics for which on-line help is available. Button 628 whenactivated provides the user the ability to obtain on-line help byselecting a region of the display. Button 630 when activated causes theprogram to terminate. As used herein, the terms “when activated,”“select” or “selected” indicate that a user, using a pointing devicesuch as a mouse, designates an area or region of a display and thenissues a command, for example by pressing a button on the mouse, whichaction is known colloquially to those of ordinary skill in the computerarts as “clicking” or “pressing” a button. Pointing devices other thanmice, such as touch sensitive displays, light pens, joysticks, or hapticinterfaces, may be used with equal effect. In some embodiments, commandscan be issued by navigating using arrow keys on a keyboard or keypad, orby the use of function keys or other specially designated keys orcombinations thereof.

FIG. 7 shows a screen shot of an embodiment of a configuration menu 700.A dialog box or window 710 is provided for the user to designate acommunication port, such as a serial port selected from the group ofCOM1, COM2, COM3, and COM4, which are conventional serial portsavailable in a conventional personal computer. The dialog box or window710 as shown has no port selected. The dialog box or window 710 includesthe conventional “drop-down window” selection mechanism indicated by thearrow button 712. The user is also provided with selections regardingsymbol reports, which can include either or both of summary and notescomponents. The user selects the desired format by marking or unmarking“check boxes” 714 and 716, respectively, for the summary and notecomponents. The user is also provided with selections regarding scanreport options. These choices are also selected by marking or unmarkingcheck boxes 720, 722, 724, 726, 728, and 730, respectively, to select asummary, report details, a scan profile, a histogram, notes, andelements widths. In the embodiment shown in FIG. 7, which is in theformat well-known to users of programs compatible with either Windows™or Apple™ computer operating systems, there are provided buttons topermit a user to select and apply his or her choices (the “OK” button),a button to exit the selection without making choices (the “Cancel”button), a “Help” button that opens an on-line help window, and the“close window” button 740, which when activated closes the configurationmenu 700. The “OK,” “Cancel,” “Help,” and “close window” buttons areubiquitous, and will not be mentioned further in explaining theinvention or its various embodiments in software. The configuration menu700 can be caused to appear as an overlay on an existing display screen,or as a separate screen, without affecting the operation of theembodiment of the invention. Other screens, such as configuration, help,or report screens, as described herein, can also be made to appear asoverlays or as separate screens, simply by making programmingselections, which selections may in some embodiments be left to thediscretion and/or preference of the user.

FIG. 8 is a screen shot of an embodiment of a menu 800 that permits auser to select the number of scans to be taken per symbol. The menu 800includes two “radio buttons” 802 and 804. Radio button 802 is selectedas a default, and provides 10 scans per symbol or encoded indiciumaccording to the conventional ISO/IEC standard. Dialog box 806 is“grayed out” when radio button 802 is selected, in the conventionalindication that the number contained within dialog box 806 is notmeaningful. Radio button 804 when selected allows the user to customizethe number of scans. When radio button 804 is selected, dialog box 806is white, and the number contained therein is the number of scans to betaken per symbol. The number can be changed by highlighting the dialogbox 806 and entering numbers from a keypad or keyboard, oralternatively, by selecting, as required, arrow 808 to increase thenumber or arrow 810 to decrease the number. When the user is satisfiedwith the selections, the “OK” button when activated applies thethen-current selections.

FIG. 5A depicts a “pull-down” menu bar 515, having a number of menuheadings, including “File,” “Settings,” “View,” and “Help.” Theheadings, when activated, cause a pull-down menu of selections toappear. For example, the “File” heading, when activated, causes menuitems titled “Open (a file),” “Save (the current file),” “Print (thecurrent file or display)” and “Exit” to appear. These are equivalent tothe functionality provided by buttons 602, 604, 606 and 630,respectively. The “Settings” heading, when activated, causes menu itemstitled “Configuration . . . ” and “Scans per Symbol” to appear, whichare equivalent to the functionality provided by buttons 608 and 610,respectively. The “View” heading, when activated, causes menu itemstitled “Previous scan,” “Next scan,” “Scan profile, “Element graph,”“Calculate X,” “Notes,” and “Reflectometer” to appear. These areequivalent to the functionality provided by buttons 61, 618, 620, 622,and 624, respectively. The “Help” heading, when activated, causes menuitems entitled “Help,” “Using help,” and “About” to appear. The “Help”menu item is equivalent in functionality to button 626. The “Using help”menu item when activated opens a help window that tells theinexperienced computer user how to use help. The “About” menu item whenactivated displays information about the program, such as versionnumber, for use when a user requests assistance, for example, from thevendor.

FIG. 9 is a screen shot of region 520 in greater detail. In thisembodiment, region 520 shows overall symbol or encoded indicium graderesults. The grade results are displayed after the selected number ofscans for the symbol has been collected, as defined according to theuser's selections. Traditionally, there is no particular number of scansthat are required to be taken to assign a symbol grade; therefore, thenumber used could be as small as one scan. However, according industrystandards, such as ISO/IEC, the number of scans required is 10 scans persymbol. The result in box 910 is a result using the industry standardISO/IEC procedures, in which an indication of “PASS” or “FAIL” appearsas each scan is taken. According to another manner of grading scans, box912 displays a result for the symbol based on a traditional scan grade,in which each scan is graded “PASS” or “FAIL” individually. Box 914 is abar graph that shows the progress of the measurement as each expectedscan is completed. The progress bar can also be used to indicate whichscan of a sequence of scans is being examined, for example when usingthe buttons 612, 614 to scroll through a series of scans. Box 916provides an alphanumeric message showing running symbol grades as eachscan is collected, and a final grade when the set of scans is completeand the last scan is displayed. The button 918 displays a letter gradeassigned to the symbol undergoing verification, which letter is a letterselected from the group consisting of “A,” “B,” “C,” “D,” and “F.”

FIG. 10 is a screen shot of an embodiment of region 530, which presentsgeneral data to a user. Box 1010 includes information comprising dataencoded in an encoded indicium or symbol. In the embodiment shown inFIG. 10, the information corresponding to a one dimensional bar codethat represents the sequence 0-2713100431-8 is presented. Thisinformation includes data and control characters. The right and leftarrows 1015 can be used to scroll through long strings of data, forexample data too long to fit completely within box 1010. In box 1020,the bar code symbology is identified as “UPC-A,” a type of UniversalProduct Code. Indicator 1030 provides a “P” or “F” indication, dependingon whether the symbology is decoded correctly. Box 1040 providesinformation about the scan direction as “FORWARD” or “REVERSE.” Box 1050indicates a degree of variation in scan speed as one of “NORMAL,”“MARGINAL” or “HIGH.” This display box can be disabled at the user'spreference, and is useful in permitting the user to assess how scans areperformed, if they are performed manually.

FIG. 11 is a screen shot of an embodiment of region 540, which displaysparameters relating to reflectance properties of the symbol beingscanned or under verification. In one embodiment, the parameters relateto contrast measurements. For each of N=1 through 8, box 11N0 is a bargraph scaled from 0% to 100% (0% is the leftmost end of the bar), inwhich the extent of a bar indicates a numeric value. Above the bar 11N0is a scale of ticks, which can be presented in colors, such as red (toindicate failure) or green (to indicate success or pass). A box 11N2provides a numerical reading of the value of the bar. In addition, inindicator 11N4, a grade in either the range A, B, C, D or F, or aPass/Fail (P/F) grade is presented, corresponding to the value of thebar in box 11N0 and box 11N2. The eight parameters are as follows: ForN=1 (e.g., boxes 1110 and 1112, and indicator 1114), R(L) or lightreflectance, is a pass for reflectances equal to or above 25%. For N=2,the parameter R(D) or dark reflectance is a pass for reflectances equalto or below 30%. For N=3, the parameter PCS, or Print Contrast Signal,is measured as the ratio of the difference of space and bar reflectanceto space reflectance, or PCS=(R(L)−R(D))/R(L). The PCS grade is PASSwhen PCS is at or above 75%; otherwise the grade is FAIL. PCS is atraditional comparison of bar and space reflectance. For N=4, theparameter SC (or Symbol Contrast) is a measure of the difference betweenthe maximum and minimum reflectances in a scan profile. The assignmentof ISO/IEC grade to symbol contrast value is given as follows: Arepresents contrast ≧70%, B represents contrast ≧55%, C representscontrast ≧40%, D represents contrast ≧20%, and F represents contrast≦20%. For N=5, the parameter Rmin/Rmax tests the ratio of a scanprofile's minimum reflectance to maximum reflectance. The ISO/IEC gradeis A if the parameter is at or below 50%; otherwise the grade is F. ForN=6, the parameter EC_(min), or Minimum Edge Contrast, is the minimum ofall edge contrasts in a scan profile. Edge contrast is the differencebetween the reflectance of a space (or quiet zone) and its adjacent bar.The ISO/IEC grade is A if EC_(min) is at or above 15%; otherwise thegrade is F. For N=7, the parameter MOD, or Modulation, is the ratio ofminimum edge contrast to symbol contrast in a scan profile. Themodulation value is lowered (along with its grade) when a scannerdetects narrow elements to have lower reflectance than wider elementsand/or detects spaces to be thinner than bars of the same printed width.The ISO/IEC grade for modulation is as follows: A represents modulation≧70%, B represents modulation ≧60%, C represents modulation ≧50%, Drepresents modulation ≧40%, and F represents modulation <40%. Finally,for N=8, the parameter Defects represents irregularities found in a scanprofile. Defects are often caused by voids or spots in the bars orspaces (including quiet zones). Within each element, the differencebetween its maximum reflectance peak and lowest reflectance valley iscalled the element reflectance nonuniformity. The parameter Defectsmeasures the ratio of the maximum element reflectance nonuniformity in ascan profile to the symbol contrast. The ISO/IEC grade as follows: Arepresents defects ≦15%, B represents defects ≦20%, C represents defects≦25%, D represents defects ≦30%, and F represents defects >30%.

FIG. 12 is a screen shot depicting region 550, which displays theISO/IEC scan grade attained by scanning an encoded indicium. The scangrade is shown graphically. Each grade is shown by a bar 1210, 1220,1230, 1240, 1250. The grade is presented as a letter grade and as anumerical grade, in which A=4, B=3, C=2, D=1 and F=0. Two colors areused, green and red, to indicate passing and failing respectively. Eachcolor can be at low or high intensity. High intensity is used to showthe grade that the scan achieved. For example, in the graphic, the scangrade is B (marked by the high intensity). Low intensity indicateswhether the grade itself is passing or failing. For example, in thegraphic above the minimum passing grade is C, (i.e., distinguished bythe low intensity switch from green to red). The B grade is passingbecause it is shown as green.

FIG. 13 is a screen shot of region 560, which displays the formatresults. Message length is displayed in box 1310. Message length is thenumber of data characters contained in a bar code. The number of messagecharacters need not equal the number of symbol characters (for instance,when Code 128 encodes two digits per symbol character). In messagelength calculations, any check characters, start/stop characters, andfunction characters are not included. Message length is usuallyspecified by application. When applicable, this parameter is graded asPass or Fail, as indicated by indicator 1320. In one embodiment, QuickCheck® PC allows an optional programmable fixed message lengthrequirement. The check character (also called check digit) is graded asPass or Fail, as indicated by indicator 1330, when selected or requiredby the symbology. A check character is a member of a bar code messagethat mathematically tests the validity of the decoded data. Checkcharacters can be specified as optional or required by a symbologyspecification. In addition, bar code labels can have additional checkdigits specified by an application. In one embodiment, Quick Check® PCallows programmable selection of optional check characters for Codabar,Interleaved 2-of-5, and Code 39. The calculation method for each isfound in the respective symbology specification.

FIG. 14 is a screen shot showing region 570 in greater detail. Theregion 570 displays various dimensional parameters associated with anencoded indicium undergoing verification. The parameters are computedbased on relative bar/space width and edge position measurements. Theparameters include decodability (1410, 1412, 1414), average bar error(1420, 1422), wide to narrow ratio (1430, 1432), and intercharacter gap(14140, 1442). The overall grade of the bar space tolerances or averagebar dimensional parameters is given as In Spec (1450), +(1452), −(1454),+Reject (1456), and −Reject (1458).

The decodability parameter is a measure of printing accuracy of a symbolrelative to the appropriate reference decode algorithm. It is the marginof error available to a bar code reader after the print process (andanything else that may occur before the bar code is read). Decodabilitycalculates this margin as a fraction of tolerance available. Thecalculation process is generally unique to a symbology and takes intoaccount the unique reading and printing aspects of that symbology. Theassignment of ISO/IEC grade to decodability value is as follows: Arepresents decodability ≧62%, B represents decodability ≧50%, Crepresents decodability ≧37%, D represents decodability ≧25%, and Frepresents decodability <25%. The decodability parameter is presented inthis embodiment as a bar graph 1410, a numerical value in box 1420, andas a letter grade in indicator 1414.

In two-width symbologies, wide to narrow ratio (or W/N ratio) is thecomparison of average wide element width to average narrow element widthexpressed as a ratio. Intercharacter gaps are never included. N usuallyrepresents W/N ratio in calculations or equations. W/N ratio is usuallyspecified in the range of 1.8 to 3.4. The reference decoding algorithmcan break down if a smaller range is specified, while higher ratios areusually discounted by practical considerations. When applicable, thisparameter grade is Pass when N is found in specification and LO or HIotherwise. Quick Check® PC allows an optional programmable W/N ratiorequirement. The value of N is displayed in box 1420, and the parametergrade is displayed in indicator 1422, as appropriate.

The intercharacter gap is the space that separates two adjacentcharacters in a discreet symbology. Symbology or application, or bothmay specify any size requirements. A value for the intercharacter gap isdisplayed in box 1420, and a grade, as appropriate, is displayed inindicator 1422.

The average bar error is an amount that bar widths differ from nominalwidth on average in a symbol. This number is expressed as a fraction ofX dimension in box 1440. A positive value indicates average bar growthand a negative value indicates bar shrinkage. Average bar error is notgraded directly, but is used to calculate what fraction of a defined bartolerance is consumed by the printing process. This traditional bartolerance calculation differs by symbology, and in the case ofU.P.C./EAN differs also by the magnification factor at which the symbolis printed. Generally a smaller X dimension yields a smaller tolerance.The tolerance ranges may be interpreted as shown in Table I, where thepercentages apply to growth or shrinkage, depending if the bar error ispositive or negative. Bar error grade is LO (negative value) or HI(positive value) when out of tolerance and Pass otherwise (whethermarginal or not). Bar tolerance is shown graphically using a scale offive “lights” on the display (i.e., 1450, 1452, 1454, 1456, and 1458).The left side of the scale indicates a negative result and the rightside indicates a positive result. In one embodiment, as indicated in thetable, high-intensity colors are used to indicate the tolerance values.

TABLE I Grade Result Color Indication <25% OK, close to nominal Green25%-50% OK, Minimal error Green + Yellow 50%-75% OK, In tolerance Yellow75%-100% OK, Marginal Yellow + Red >100% Fail, Out of tolerance Red

FIG. 15 is a screen shot of region 580, which section of the displayshows certain informative and graded results as a list of text messagesin box 1510. These format and dimensional results are in a list formatto save on the amount of custom graphic areas that would otherwise benecessary. The messages are scrolled using the up and down arrow buttons1520, 1522. The indicator, which in one embodiment is a grade bubble,indicates that a failing result is included in the list if red or ifdisplaying the letter F, or both. Table II below lists messages that inone embodiment are provided as necessary, and their meanings.

TABLE II Message Displayed: Meaning of the Message: BAD # SystemU.P.C.-E1 symbol was scanned BAD Char Seq. Error in Code 128 modecharacter placement RefDecode FAILS Reference decode algorithm failedGlobalThr FAILS Global threshold conformance failed SHORT Left QZ Leftquiet zone failed minimum requirement SHORT Right QZ Right quiet zonefailed minimum requirement BAD Left Guard U.P.C./EAN left guard patternfailed conformance test BAD CenterGuard U.P.C./EAN center guard patternfailed conformance test BAD Right Guard U.P.C./EAN right guard patternfailed conformance test UCC/EAN-128 Errors UCC/EAN-128 format errors, ifany, are listed UCC/EAN-128 A.I.s UCC/EAN-128 application identifierdescriptions, if applicable, are listed BAD AddendumChk U.P.C./EANaddendum failed parity check 100% Mag Factor U.P.C./EAN magnificationfactor is reported X = 0.0001 in X dimension, if measured, is reportedTotal = 99 X Symbol width in terms of X dimension is reported if Xdimension is not calculated Quiet Zones OK Displayed if both quiet zonetests passed Ref.Decode OK Displayed if reference decode passed

The global threshold is the reflectance level that is the midpointbetween a scan profile's maximum and minimum reflectance. It is definedthat all edges of elements shall traverse the global threshold; thuseach space's reflectance value is above and each bar's reflectance valueis below the global threshold. The point on a scan profile thatintersects the midpoint between adjacent bar and space reflectancesdetermines edges. The global threshold grade is A if all elementsconform to this test; otherwise the grade is F.

Each symbology has an associated reference decode algorithm, defined ina symbology specification or a particular application, or perhaps both.This algorithm is used to decode the symbol using the elements definedby those edges that conform to the global threshold test. If thereference decode is successfully completed, then this grade is A;otherwise this grade is F. Note that if the scan profile fails globalthreshold, then reference decode automatically fails since not allelements could be determined.

Quiet zones, also called light margins, are areas of space at the endsof a bar code. By separating bar codes from other surrounding markings,quiet zones help increase reading security. Symbology or application, orboth can specify quiet zone requirements. Left and right quiet zones areseparately graded as Pass or Fail. The grade reported is OK or F.

Symbol Total is the width of the bar code symbol, excluding quiet zones,expressed as a multiple of X dimension. With U.P.C./EAN symbols, thiswidth is excluding any addendum. Symbol total facilitates calculation ofthe X dimension. If the physical width of the symbol is known(relatively easy to measure with a ruler), symbol width divided bysymbol total yields the X dimension in the units in which the width wasmeasured. In one embodiment, Quick Check® PC has a dialog window whichdoes the calculation given the physical symbol width. This parameter isnot graded but is reported for informational purposes only.

Magnification Factor is the amount of uniform scaling applied to asymbol to enlarge or reduce that symbol from nominal size (where nominalis usually 100%). The U.P.C. symbology, which is traditionally specifiedby physical dimensions, is a notable example where magnification factorapplies. Bar tolerance calculations for U.P.C./EAN depends on themagnification at which the symbol is printed. Magnification factor mustbe selected manually in one embodiment of Quick Check® PC.

FIG. 5B shows an embodiment of the self-aligning image quality verifiersystem that employs a user interface screen 500 on a video display. Inaddition to a toolbar 510, a “pull-down” menu bar 515, and a pluralityof regions 520, 530, 540, 550, 560, 570 and 580, FIG. 5B also depicts aregion 590. Region 590 is a status bar that displays the then currentprogram conditions. FIG. 16 is a screen shot of the region 590 statusbar. The status bar 590 is divided into different message areas. Area1610 displays general status and help messages. Area 1620 displaysinformation about the scanner type that is being used. In oneembodiment, area 1620 shows aperture and illumination wavelength of thedetected pen or mouse wand. If the scanner is removed, the message shownis “Scanner Missing!” If the interface box is off or disconnected, themessage shown is “No Connection!” If no serial port is selected, themessage shown is “No Port Selected!” In area 1630 there is shown theordinal number of the scan that is currently displayed out of theexpected number of scans per symbol. In area 1640, there is anindication of the selected serial port. If the box is empty, no port hasbeen selected. GUI 1650 is an icon in the shape of a battery. This iconappears when low battery level is detected, warning that the interfacemay shut down. In the event of such shutdown, no PC data is lost. Theicon is not shown normally. GUI 1660 is a hardware status indicator thatacts like an LED, using color to indicate various interface statusconditions. GUI 1660 is gray when interface is off or port selectiondoes not match the actual connection. GUI 1660 is red when the interfaceis detected but not active, such as when the scanner is removed or QuickCheck® PC has paused operation. GUI 1660 is green when the interface isactive and ready to scan.

Those of ordinary skill will recognize that many functions of electricaland electronic apparatus can be implemented in hardware (for example,hard-wired logic), in software (for example, logic encoded in a programoperating on a general purpose processor), and in firmware (for example,logic encoded in a non-volatile memory that is invoked for operation ona processor as required). The present invention contemplates thesubstitution of one implementation of hardware, firmware and softwarefor another implementation of the equivalent functionality using adifferent one of hardware, firmware and software. To the extent that animplementation can be represented mathematically by a transfer function,that is, a specified response is generated at an output terminal for aspecific excitation applied to an input terminal of a “black box”exhibiting the transfer function, any implementation of the transferfunction, including any combination of hardware, firmware and softwareimplementations of portions or segments of the transfer function, iscontemplated herein.

While the present invention has been explained with reference to thestructure disclosed herein, it is not confined to the details set forthand this invention is intended to cover any modifications and changes asmay come within the scope of the following claims.

1. A self-aligning structure for use in measuring the quality of anencoded indicium, comprising: a hollow chamber comprising: a firstsurface defining a first aperture, the first aperture representing aviewing area of an imager used to obtain an image of the encodedindicium; a second surface defining a second aperture, the secondaperture configured to support the imager in a position to obtain theimage of the encoded indicium; at least one source of illuminationsituated within the hollow chamber, the at least one source ofillumination configured to illuminate the encoded indicium; and anillumination control operatively coupled to control the at least onesource of illumination; the hollow chamber configured to be positionedadjacent the encoded indicium such that, when the encoded indicium ispositioned within the viewing area, when an imager is supported in thesecond aperture, and when the at least one illumination source isproperly controlled, the structure is self-aligned and the imager canobtain at least one image of the encoded indicium from which image thequality of the encoded indicium can be measured, wherein the hollowchamber is constructed in a plurality of mating sections, a firstsection comprising the first surface defining the first aperturerepresenting the viewing area of the imager of the encoded indicium, anda second section comprising the second surface defining the secondaperture configured to support the imager in the position to obtain theimage of the encoded indicium.
 2. The self-aligning structure accordingto claim 1, wherein the hollow chamber is configured to excludeextraneous illumination when the imager is present and the hollowchamber is positioned adjacent the encoded indicium.
 3. Theself-aligning structure according to claim 1, wherein the hollow chamberis configured to support the imager in a defined position relative tothe encoded indicium.
 4. The self-aligning structure according to claim3, wherein the defined position comprises a defined distance.
 5. Theself-aligning structure according to claim 3, wherein the definedposition comprises a defined angle.
 6. The self-aligning structureaccording to claim 1, wherein said hollow chamber is constructed so thatsaid second section is adapted to be disposed on top of said firstsection.
 7. The self-aligning structure according to claim 1, whereinthe hollow chamber is configured to remain mechanically stable when theimager is positioned within the second aperture.
 8. The self-aligningstructure according to claim 1, wherein the hollow chamber furthercomprises an optical sensor configured to receive illumination from theat least one source of illumination for the purpose of confirming anillumination characteristic provided by the at least one source ofillumination.
 9. The self-aligning structure according to claim 8,wherein the illumination characteristic provided by the at least onesource of illumination is a characteristic selected from an illuminationintensity at a selected time and an illumination wavelength.
 10. Aself-aligning structure for use in measuring the quality of an encodedindicium, comprising: a hollow chamber comprising: a first surfacedefining a first aperture, the first aperture representing a viewingarea of an imager used to obtain an image of the encoded indicium; asecond surface defining a second aperture, the second apertureconfigured to support the imager in a position to obtain the image ofthe encoded indicium; at least one source of illumination situatedwithin the hollow chamber, the at least one source of illuminationconfigured to illuminate the encoded indicium; and an illuminationcontrol operatively coupled to control the at least one source ofillumination; the hollow chamber configured to be positioned adjacentthe encoded indicium such that, when the encoded indicium is positionedwithin the viewing area, when an imager is supported in the secondaperture, and when the at least one illumination source is properlycontrolled, the structure is self-aligned and the imager can obtain atleast one image of the encoded indicium from which image the quality ofthe encoded indicium can be measured, wherein said self-aligningstructure is configured to receive illumination from the at least onesource of illumination for the purpose of confirming an illuminationcharacteristic provided by the at least one source of illumination. 11.The self-aligning structure according to claim 10, wherein theillumination characteristic provided by the at least one source ofillumination is a characteristic selected from an illumination intensityat a selected time and an illumination wavelength.
 12. The self-aligningstructure according to claim 10, wherein the illumination characteristicprovided by the at least one source of illumination is an illuminationintensity.
 13. The self-aligning structure according to claim 10,wherein the illumination characteristic provided by the at least onesource of illumination is an illumination wavelength.
 14. Theself-aligning structure according to claim 10, wherein the self-aligningsensor includes an optical sensor separate from said imager forreceiving illumination for the at least one source of illumination forthe purpose of confirming an illumination characteristic provided by theat least one source of illumination.
 15. An image quality verifiersystem useful for verifying the quality of an encoded indicium, thesystem comprising: a first imager for obtaining an image of said encodedindicium; a second imager for obtaining an image of said encodedindicium; at least one source of illumination for illuminating saidencoded indicium; and a structure comprising a hollow chamber, thehollow chamber configured to exclude extraneous illumination andcomprising a first surface defining a first aperture, the first aperturerepresenting a viewing area of the imager, wherein said structure isconfigured to support, at any given time, one of said first imager andsaid second imager at a position above said encoded indicium, whereinsaid structure is further configured so that when said first imager issupported by said structure, said first imager is in such position toobtain an image of an indicium within said viewing area, and whereinsaid structure is further configured so that when said second imager issupported by said structure said second imager is in such position toobtain an image of an indicium within said viewing area.
 16. The imagequality verifier system of claim 15, wherein said first imager and saidsecond imager have different working distances.
 17. The image qualityverifier system of claim 15, wherein said structure comprising saidhollow chamber includes a hollow chamber having a first section definingsaid first aperture and an interchangeable second section comprisingeither a first second section or an alternate section, the system beingconfigured so that said first second section is mated to said firstsection for supporting said first imager, the system further beingconfigured so that said alternate second section is mated to said firstsection for supporting said second imager.
 18. The image qualityverifier system of claim 15, wherein said hollow chamber of saidstructure supports one of said first imager or said second imager. 19.The image quality verifier system of claim 15, wherein each of saidfirst and second imagers includes an illumination source so that saidsource of illumination of said system for illuminating said encodedindicium can be provided by said first or second imagers, whichever issupported by said structure.
 20. A self-aligning structure for use inmeasuring the quality of an encoded indicium, comprising: a hollowchamber comprising: a first surface defining a first aperture, the firstaperture representing a viewing area of an imager used to obtain animage of the encoded indicium; a second surface defining a secondaperture, the second aperture configured to support the imager in aposition above said encoded indicium to obtain the image of the encodedindicium, wherein said hollow chamber is provided in a form having firstand second mating sections, the hollow chamber being configured so thatsaid first surface defining said first aperture is included on saidfirst mating section and said second surface defining said secondaperture is included on said second mating section.
 21. Theself-aligning structure of claim 20, wherein said structure is providedin a form including an alternate first section of said hollow chamber,and wherein said hollow chamber is configured so that said alternatefirst section can replace said first section.
 22. The self-aligningstructure of claim 20, wherein said structure is provided in a formincluding an alternate first section of said hollow chamber, whereinsaid hollow chamber is configured so that said alternate first sectioncan replace said first section, and wherein the alternate first sectionhas a viewing area defined for a different type of encoded indicium thansaid first section.
 23. The self-aligning structure of claim 20, whereinsaid structure is provided in a form including an alternate secondsection of said hollow chamber, and wherein said hollow chamber isconfigured so that said alternate second section can replace said secondsection.
 24. The self-aligning structure of claim 20, wherein saidstructure is provided in a form including an alternate second section ofsaid hollow chamber, wherein said hollow chamber is configured so thatsaid alternate second section can replace said second section, andwherein said alternate second section is configured to support adifferent imager than said second section.
 25. An image quality verifiersystem useful for verifying the quality of an encoded indicium,comprising: an imager for obtaining an image of the encoded indicium; asource of illumination for illuminating said encoded indicium; and ahollow chamber configured to exclude extraneous illumination andcomprising a first surface defining a first aperture, the first aperturerepresenting a viewing area of the imager, wherein said system isconfigured so that said imager is positioned at a position above saidencoded indicia, wherein said system is provided in a form such that asection of said hollow chamber including said first surface can beremoved from a remainder of said hollow chamber and replaced with analternate hollow chamber section.
 26. The image quality verifier systemof claim 25, wherein said alternate hollow chamber section is configuredfor use with a different type of encoded indicium than said section ofhollow chamber including said first surface.
 27. An image qualityverifier system useful for verifying the quality of an encoded indicium,comprising: an imager for obtaining an image of the encoded indicium,the imager comprising a sensor including one of (i) a linear array ofphotosensitive elements or (ii) two dimensional array of photosensitiveelement; a source of illumination for illuminating said encodedindicium; a hollow chamber configured to exclude extraneous illuminationand comprising a first surface defining a first aperture, the firstaperture representing a viewing area of the imager, the hollow chamberalso having a second surface at a position above said first aperture,wherein said system is configured so that said imager is supported at aposition that is above said encoded indicia and proximate said secondsurface of said hollow chamber that is configured to exclude extraneousillumination; and an analysis module in wireless radio communicationwith said imager, said analysis module including a memory device and aprogrammed microprocessor, said analysis module in communication withsaid imager being configured to analyze an image to extract therefrominformation regarding the quality of said encoded indicium.
 28. Theimage quality verifier system of claim 27, wherein said source ofillumination is incorporated in said imager.
 29. The image qualityverifier system of claim 27, wherein said source of illumination isincorporated in said chamber.
 30. The image quality verifier system ofclaim 27, wherein said sensor is a two dimensional array ofphotosensitive elements.